Carburetor



April 6, 1926. 1,5793% A. M. LA GHAPELLE CARBURETOR Original FiledMaIfCh 15, 1920 INVEN To Patented Apr. 6, 1926.

UNITE STATES ALFRED M. LA GHAPELLE, OF CHICAGO, ILLINOIS, ASSIGNOR TO I.H. P. PRODUCTS COMPANY, A CORPORATION OF DELAWARE.

CARBURETOR.

Refiled for abandoned application Serial No. 366,074, filed March 15,1920. This application filed November 16, 1920. Seria1 No. 424,491.

To (ZZZ whom 2'25 may concern:

Be it known that I, ALFRED M. LA CHAP- ELLE, a citizen of the UnitedStates, residing in Chicago, in the county of Cook and State ofIllinois, have invented certain new and useful Improvements inCarburetors, of which the following is a specification.

This invention relates to improvements in carburetors.

The carburetor herein, illustrated as embodying my invention is of thetype in which a free body of fuel is maintained at a predetermined leveland with the fuel surface exposed to the suction of the engine, saidbody of fuel being automatically replenished from a source of supply bythe suction created by the engine.

An object of the present invention is to provide a carburetor in whichthe amount of air drawn into the carburetor is controlled by an exteriorthrottle valve, which throttles the motor and creates a positive vacuumfeed within the carburetor. It is also an. object to provide means toautomatically control the relative proportions of fuel and air for allmotor speeds.

Another object of the invention is to so construct the carburetor thatit may be manufactured at a minimum cost and with parts which may bereadily assembled.

With these and other objects in view my invention consists in the novelconstruction, combination and relative position of the parts and membershereinafter described and shown in the accompanying drawings, andparticularly pointed out in the appended claims.

Referring to the drawing in which like reference characters indicatelike or corresponding parts:

Fig. 1 represents a vertical central sectional view through my improvedcarburetor.

Fi 2 re resents a horizontal sectional View through the same, the planeof the section indicated by line 22 of Fig. 1.

Fig. 3 represents the bottom view of the carburetor.

Fig. 4 represents a detail sectional view through the carburetor in aplane indicated by the line l t of Fig. 1.

Referring-i l: detail to that embodiment of my invention illustrated inthe accompanying drawings: 5 indicates the bowl of the carburetor whichis open at the top and has a bottom wall 6 from which depends an annularflange 7. In the flange 7 is of annularly spaced ports or defines apassageway through the bowl 5,

and the space between the tube 9 and the upright wall of the bowlprovides an annular reservoir for the fuel.

10 indicates as a whole a cover or top wall for the carburetor bowl vThe cover 10 comprises an upright tubular neck 11 which terminates atits lower end in a horizontally disposed flange 12. This flange 12 seatsat its peripheral margin on the top of the bowl and forms a closure forthe same. The cover 10 may be secured to the top edge of the bowl byextending ears and screws as shown or by any other means. To make atight joint a gasket 13 is interposed between the top edge of the bowl 5and the cover flange 12 which secures a gas tight joint. The top end ofthe tubular neck 11 has the usual connection flange by which thecarburetor is attached to the inlet manifold of the motor.

14 indicates an upwardly extending hollow boss formed on the top surfaceof the cover flange l2 and near its outer edge. This boss 14 has athreaded aperture 14 for connection with a fuel supply line at one endand a communicating aperture 14: at the other end which opens throughthe flange 12 into the annular fuel chamber. A tubular valve guide 15has threaded engagement in the aperture 149 and depends into the fuelchamber. l/Vithin the top end of the valve guide 15 is formed adownwardly facing valve seat 15 against which a valve 17 is adapted toclose. Within the fuel chamber and surrounding the upright tube 9 is asuitable float 16 pivoted to the bottom end of the valve guide 15 insuch manner 7 that the opening and closing of the valve 17' is regulatedby the height or quantity of the fuel in the fuel ch.

20 indicates an upright tube concentrically arranged within the uprighttube 9 and constituting the primary air inlet tube for the carburetorand extending at its ends above and below the upright tube 9. The topend of the tube 20 which is enlarged in diameter as at 2-, extends intothe passageway defined by (110 tubular neclt ll of'the cover 10. Thetube 20 is supported at its upper end within the upright tube S) bymeans of the tube 2- which forms the fuel atomizing or spray tube andwhich here preferably snown in an inverted U-shape. This atomizing tubecomprises a horizontal leg 22, which extends through suitable aperturesin the enlarged part of the tube 20, and vertical legs 22", 22", whichare brazed or otherwise at.a "led to the tube 9, as shown. Thehorizontal leg 2-2 has vertically aligned atomizing openings 23, 23,which are coaxial or concentric with the tube 20, and the bottom ends ofthe vertical legs 22" have openii in communication with the bottom ofthe fuel chamber through openings 24:, 24;, in the upright tube 9, tothereby afford a supply of fuel from the fuel chamber to both ends ofthe atomizing tube The depending annular flange 7 is closed at itsbottom end by a plate 25, and thus provides a valve casing for asecondary air in let valye 26 which is adapted for vertical movement insaid casing. The seconcary air valve comprises a disc 2? which normallybears upon the bottom wall or plate 25 of the valve casing and anupright annular sleeve 28 having ports 28 which are adapted to registerwith the ports 8 in the flange 7 when the valve 26 in its raisedposition. An upright inner integral sleeve 29 embraces the lower end ofthe tube 20 and is operatively slidable over same. light helicalexpansion spring 29 coiled around the tube 20 is interposed between thedisc 2. of the valve and a shoulder 36 formed at the unction of theenlarged part 21 and the main body of the tube 20.

The plate 25- which provides the bottom vall of the secondary air valvecasing has av depending tubular extension 31 which is coaxial orconcentric with the primary air tube 20. This extension 31 and innersleeve form in effect a continuation of the primary air tube 20. Thesleeve 29 is integrally attached to valve 26. In the extension 31 islocated the throttle valve which valve 32 is fixed on a rocl; shaft 33having support in the extension and in a bearing ear 25 formed integralwith the plate A suitable operating arm 3st controls the movement andposition of the valve Thus the throttle valve 32 controls the ad missionof air into and through the carburetor, which will be more fullyhereinafter.

In the operation of my carlan'etor and assuming that the fuel chamber isempty and that the fuel supply tanli is located in a plane below that ofthe carburetor, the annular float 16 is therefore in its lowest positionin the fuel chamber and the valve 17 in open position allowing of a freepassageway from the fuel chamber through the tucl supply line to thefuel supply tank which has an opening admitting atmos 'ihcric pressuretherein. The secondary airwalve it; is in its normal position at thebottom or its casing and closing the annular poi-ts 8 in the flange Tand the spring 29 serving to further hold said valve in this positionUnder these conditions, and in order to draw or suck the fuel from thesupply tanl; into the fuel chamber, itis desirable to have the throttlevalve in the tubular extension 11 of the plate 25 in a closed position.

The crank shaft of the engine is now turned over in the usual manner.The suction stroke of the pistons will lirst displace the air from theinterior of the carburetor (it being remembered that the throttle valveis closed) and will produce a partial vacuum therein. This vacuum willactto draw or such into the fuel chamber, a quantity of fuel from thefuel supply tanl: through the supply line and open valve 17. and as thefuel level rises in the fuel chamber the float will raise the stem 18and valve 1T and the passageway into the fuel chamber from the supplyline will be closed and the fuel will have reached a predeterminedlevel. It apparent that as the fuel enters the fuel chamber, it willflow through the openings 2%, 24, and into the vertical legsof theatomizing tube. The throttle valve does not necessarily have to beclosed air-tight since the great demand for air created by the impulseof the motor will be sufficient to meet the required vacuum to draw thefuel from the supply tank into the carburetor regardless of any slightleakage around the throttle valve, and closed position which may beadjustably varied for the idle running of the motor. It is obvious thatthe air thus passing through the throttle opening and through theprimary air tube on the way to the en gine cylinders will creat adraught in passing through and around the atomizing tube 22 which willdraw the fuel up the vertical legs 22" into both ends of the horizontalsection 22". From the drawings it will be seen that the space betweenthe bottom of the air valve 26 and the plate 25 in open com municationwith the bottom open end of the primary air tube and thatany suctionexerted in the carburetor will be equally exerted upon both top andbottom of the secondary air valve 20, and further that the suctionexerted upon the upper surface of explained the valve 26 cannot raisethe valve 26 unless the pressure against the outside of the valve isrelatively greater than the opposing forces including the weight of thevalve and the pressure of the spring 29. Therefore, said secondary airvalve will not rise to aposition where the ports 8 and 28 will register.until sutlicient air is admitted through the throttle opening 31 tocounteract the reduced pressure immediately above the throttle valve 32,it being remembered that the valve 26 is under reduced pressure whilethe engine is running. In this manner the throttle valve 32 governs theopening of the second ary air valve 26 and the admission of all the airinto the carburetor. The spring 29 opposes the opening of the valve 26to a pre determined degree of pressure and in this manner sufficientsuction is maintained in the carburetor to draw fuel from a supply tankof a level lower than the carburetor and when the motor is running witha wide open throttle valve at a very low speed.

In controlling the speed of the motor, the manipulation of thecarburetor is similar to those having the throttle valve at thecarburetor outlet and between the fuel device and the engine intakemanifold. The difference, however, lies in the fact that when thethrottle valve in the carburetor herein shown is closed, the suction orvacuum in the carburetor increases while in the aforesaid conventionaltype now in use, the suction or vacuum decreases. The arrangement hereinprovided affords the utilization of the suction or vacuum, to produce apositive feed apparatus for supplying fuel to the carburetor, and tocause the fuel to vaporize more readily than is possible at atmosphericpressure. This is of great importance since most of the driving of motorvehicles is under conditions with the throttle valve partially closed.

As has been explained, the opening of the secondary air passage iscontrolled by the throttle valve 32 and that when the motor speed is lowand the throttle valve 32 is wide open, the spring 29* will maintain agiven amount of suction in the carburetor in the space above the valve26 by retaining the secondary air valve in a closed or partly closedposition against a suction which is sufiicient to draw fuel to thecarburetor from a given level below the carburetor. The amount ofsuction exerted by the motor is equally exerted in all parts of thecarburetor and because of this the amount of fuel is proportioned to theincoming air by the draught created by the air in passing through andaround the atomizing tube 22 that is, as the velocity of the airincreases, the fuel raised from the fuel chamber into said tube 22 willincrease in proportion. The jet of air passing through the openings 23and 23 affords an automatic fuel metering means. A smaller volume offuel will pass through the opening 23 into the jet of air at lowvelocity than will at a higher velocity. In this manner the proportionsof the mixture are maintained when secondary air is admitted.

I claim:

l. A carburetor for combustion engines comprising a bowl having anupright wall, an inwardly extending flange forming a bottom therefor, anupright tube adapted to be fixed to the inner edge of said flange, andextending to a point adjacent the upper periphery of said upright wall,said upright tube, flange and upright wall defining a fuel chamber, aninverted U-shape spray tube within said upright tube, the upright legportions of said tube being connected with said fuel chamber and in opencommunica tion therewith, an air inlet tube supported on the upperportion of said spray tube, said U-shaped spray tube being provided withapertures aligned with said air inlet I tube, said air inlet tubeextending downwardly below the bottom of said bowl, anc communicatingwith the atmosphere, it throttle valve controlling the admission of airinto said air inlet tube, an auxiliary air valve between said fuelchamber and said throttle valve and resilient means normally 90maintaining said auxiliary air valve in closed position, said auxiliaryair valve being arranged to admit air into said upright tube and aroundsaid air inlet tube for admixture with the air passing through the upperend of said air inlet tube, and the relative opening of said auxiliaryair valve being controlled by the opening of said throttle valve and thespeed of the engine.

2. A carburetor for combustion engines comprising a bowl having anupright wall, an inwardly extending integral flange forming a bottomtherefor, an upright tube adapted to be fixed to the inner edge of saidflange and extending to a point adjacent the upper periphery of saidupright wall defining a fuel chamber, a combined cover and neckpositioned above said fuel chamber, the space between the upperperiphery of the upright tube and said cover being restricted, aninverted U-shaped spray tube within said upright tube, the upright legportions of said tube being connected with said fuel chamber and in opencommunication therewith, an air inlet tube sup- 1 ported on the upperportion of said spray tube, said U-shaped tube being provided withapertures aligned with said air inlet tube, said air inlet tubeextending downwardly below thebottom of said bowl and communicating withthe atmosphere, a throttle valve controlling the admission of air intothe said air inlet tube, an auxiliary air valve between said fuelchamber and said throttle valve, and resilient means nor- 130 inallymaintaining said au.\:iliar air valve in closed position, said auxiliaryair valve being arranged to admit air into said upright tube and aroundsaid air inlet tube for admixture With the air passing through the upperend of said air inlet tube, and the relative o iening of said auxiliaryair valve being controlled by the opening of said throttle valve and thespeed of the engine.

In witness whereof, I h ve hereunto sub- 10 scribed my name this 12thday of November 1920.

ALFRED M. Li CHAPELLE.

